Phosphatidylserine induces apoptosis in CHO cells without mitochondrial dysfunction in a manner dependent on caspases other than caspases-1,-3,-8 and-9

Treatment of Chinese hamster ovary KI cells with phosphatidylserine (PS) ca used typical apoptosis with distinct morphological and biochemical features in a dose- and time-dependent manner. However, unlike camptothecin-induced apoptosis, changes in mitochondrial transmembrane potential were not obser ved. In addition, cytochrome c release did not occur in PS-induced apoptosi s. A pan caspase inhibitor, Z-VAD, significantly inhibited the apoptosis, b ut inhibitors of caspase-1, -3, -8 and -9 did not. Activities of caspase-1, -3, -8 and -9 were increased by treatment of the cells with camptothecin, but not with PS. These results suggest that PS-induced apoptosis occurs wit hout the collapse of mitochondrial transmembrane potential and without the release of cytochrome c, in a manner independent of caspase-1, -3, -8 and - 9. (C) 2001 Federation of European Biochemical Societies. Published by Else vier Science B.V. All rights reserved.